Coronary flow dynamics in children after repair of Tetralogy of Fallot.

Objectives: To assess the possible effect of a stiff right ventricle on the coronary flow (CF) in patients with post-operative Tetralogy of Fallot (TOF).

Background: Right ventricular restrictive physiology i.e. forward flow during atrial contraction (RVRP), is characteristic to many patients with post-operative TOF.

Methods: A total of 34 patients with TOF anatomically corrected through transatrial repair were included. Coronary flow parameters were registered with transthoracic Doppler echocardiography from posterior descending (PDCA) and left anterior descending (LAD) coronary arteries in the same patient in 24/34 (71%) patients. Twenty age-matched healthy children were used as controls. Cardiac magnetic resonance (CMR) imaging was used to detect myocardial fibrosis, RV volume, and RVRP.

Results: The mean age at investigation was 10.2 ± 2.8 years. RV end diastolic and end systolic volumes indexed for BSA were larger in patients with RVRP (p=0.002 and 0.008 respectively). Peak flow velocity in diastole and flow velocity time integral was increased in patients compared to controls. They were increased in the LAD in patients with fibrosis of RV (n=11) compared to patients without fibrosis (n=9) (p=0.01 and 0.047 respectively). LAD coronary flow was especially increased in patients with RVRP (n=9) as compared with those without (n=11), (p=0.006).

Conclusions: Patients at mid-term followup after correction of TOF show increase of coronary flow. This increase is more pronounced in patients with fibrosis and RVRP of the RV.